This thesis is missing page 57, this page is not in any of the other copies. -Digitization Centre / Scientists believe that the global climate is undergoing significant changes due to anthropogenic increases of carbon dioxide (CO2) and other Greenhouse gases. The relationship between climate and vegetation is not fully understood. Knowledge of the response of vegetation to past climate change aids in the understanding of potential vegetation responses to climatic changes due to the Greenhouse effect. The objectives of this thesis were to determine if vegetation in the lower Lena River Region has changed in the past, what were the factors which caused the changes and over what time scales did the changes occur. To address the objectives, the pollen, stomate and sediment stratigraphy of a core from a medium size lake, located in north-central Siberia, were analysed. Radiocarbon dating indicates that the record spans the last 12310 yr BP, and possibly the last 15000 yr BP. The early part of the fossil record was characterised by short rapid changes in the vegetation. The initial shrub tundra was quickly replaced by herb tundra with sparse vegetation cover. This was followed by a reversion to shrub tundra conditions at ~12000 yr BP. A clear Younger Dryas signal is found in this record between 11000 and 10000 yr BP, characterised by a shift from shrub tundra to herb tundra dominated by taxa with arctic affinities. The warming at the close of the Younger Dryas signalled the first appreciable climatic amelioration at this site. Following 10000 yr BP, Alnus became abundant in the pollen record and likely on the landscape. The dominance of Alnus was short lived however. At ~8500 yr BP arboreal vegetation, dominated by Larix dahurica, became abundant in the pollen and stomate record. The expansion of forests was the result of changes in the orbital parameters of the earth as predicted by Milankovitch cycles. Arboreal vegetation persisted in this region until-3500 yr BP when the modem shrub tundra vegetation was established. The use of a new technique, stomate analysis, proved extremely useful. Stomates accurately recorded the expansion and retreat of treeline across this region. This study clearly indicates the usefulness of this technique, especially for investigating fluctuations of treeline. / Thesis / Master of Science (MS)

Background: Lower limb amputees face many challenges, and most of them prefer to use prosthetics for daily tasks and activities. The prosthesis is usually a combination of connected prosthetic components, and their spatial orientation is called the prosthetic alignment. Proper alignment is essential, as it substantially affects the quality and comfort of a prosthesis.   Objective: The aim of this study was to create a method that could accurately and effectively quantify the alignment of a transtibial and transfemoral prostheses using Vicon optical motion capture system.   Methods: Two experimental series were conducted. The first one was to test the repeatability of the measurement. Three analysts placed retroreflective markers on the prostheses three times, and five measurements were recorded each time. Alignment parameters were calculated in Vicon ProCalc for each measurement, and a standard error of measurement was found for each alignment parameter. The standard error of measurement was calculated from three variance components, between-analyst, within-analyst, and between-trial variability. The second experimental series was conducted to understand the relationship between alignment adjustments and the outcome parameters. The socket height, internal rotation, flexion, adduction, and translation were modified and measured. The socket translation was calculated in three coordinate systems to study how they affect the outcome.   Results: For the first experimental series, the standard error of measurement for every alignment parameter was below 3° and 6 mm. The between-analyst variability was the most prominent, and the parameters calculated in the sagittal plane were more reliable than those calculated in the frontal and transverse plane. In the second experimental series, there was a linear relationship between the modifications and the measured outcome. When a connection between two prosthetic components was changed by turning the screws one round, the average change in angle between them was 2°, and the average translation change was 4.4 mm. Of the three coordinate systems, the translation calculated in ankle coordinates was more reliable than in global coordinates and describe the translation more effectively than in socket coordinates.   Conclusion: The reliability of the measurements was considered good. The standard error of measurement was low, and the main variability resulted from differences in marker placement between the analysts. The results from the measured alignment changes were as expected. All the parameters could be effectively interpreted, and the ankle coordinates were considered advantageous in describing the socket translation.

In this thesis, we generate a lower bound on the security of quantum protocols for secure function evaluation. Central to our proof is the concept of gentle measurements of quantum states, which do not greatly disturb a quantum state if a certain outcome is obtained with high probability. We show how a cheating party can leverage gentle measurements to learn more information than should be allowable. To quantify our lower bound, we reduce a specific cryptographic task known as die-rolling to secure function evaluation and use the concept of gentle measurements to relate their security notions. Our lower bound is then obtained using a known security bound for die-rolling known as Kitaev's bound. Due to the generality of secure function evaluation, we are able to apply this lower bound to obtain lower bounds on the security of quantum protocols for many quantum tasks. In particular, we provide lower bounds for oblivious transfer, XOR oblivious transfer, the equality function, the inner product function, Yao's millionaires' problem, and the secret phrase problem. Note that many of these lower bounds are the first of their kind, which is a testament to the utility of our lower bound. As a consequence, these bounds prove that unconditional security for quantum protocols is impossible for these applications, and since these are constant lower bounds, this rules out any form of boosting toward perfect security. Our work lends itself to future research on designing optimal protocols for the above listed tasks, and potentially others, by providing constant lower bounds to approximate or improve. / Master of Science / Quantifying the cryptographic security of quantum applications is the focus of much research in the quantum cryptography discipline. Quantum protocols might have better security than their classical counterparts, and this advantage might make the adoption of quantum cryptographic protocols a viable option. In this thesis, we introduce a method for generating constant lower bounds on the security of a variety of quantum applications. This is accomplished through finding a lower bound on the security of a protocol that is general, and by virtue of its generality, can be scoped to quantum applications such that the lower bound can be applied, and constant lower bounds generated for these applications. The significance of the work in this thesis is that many of the constant lower bounds presented are the first of their kind for these quantum applications, thus proving the impossibility of them having unconditional security. This also proves that one cannot asymptotically boost towards perfect security in these quantum tasks by any means. These constant lower bounds also provide a foundation for future work in the study of these quantum applications, specifically in the search for upper and lower bounds on their cryptographic security, as well as in the search for protocols that approximate these bounds.

Obese and older adults are reported to have a higher rate of mobility limitation and are at a higher risk of fall compared to healthy-weight and young counterparts. To help identify potential mechanisms of these mobility limitations and higher risk of falls, the purpose of the research within this dissertation was to investigate the effects of obesity and age on muscle strength, gait, and balance recovery. Three experimental studies were conducted. The purpose of the first study was to investigate the effects of obesity and age on extension and flexion strength at the hip, knee, and ankle. Absolute strength among obese participants was higher in dorsiflexion, knee extension, and hip flexion compared to healthy-weight participants. Strength relative to body mass was lower among obese participants in all joints/exertions. This lack of uniformity across the 6 exertions is likely due to the still unclear underlying biomechanical mechanism responsible for these strength differences, which may also be influenced by aging. The purpose of the second study was to investigate the effects of obesity, age and, their interactions on relative effort at the hip, knee, and ankle during gait. The peak relative effort for each joint/exertion was expressed by peak NMM during gait as a percentage of the maximum available NMM. The relative effort in hip, knee, and ankle was higher among obese compared to healthy-weight participants. This higher relative effort in hip, knee, and especially in the ankle can be a contributing factor to compromised walking ability among obese individuals. The purpose of the third study was to investigate the effects of age-related strength loss on non-stepping balance recovery capability after a perturbation while standing, without constraining the movements to ankle strategy. The balance recovery capability was quantified by the maximum recoverable platform displacement (MRPD) that was withstood without stepping. Two experiments were conducted. The first experiment involved human subjects and the results suggested that MRPD was lower among older participants compared to young participants. The second experiment involved a simulation study to manipulate muscle strength at hip, knee, and ankle. The results suggested that MRPD was reduced in cases of loss of strength in ankle plantar flexion and hip flexion compared to the young model and did not differ in rest of the cases. The finding suggested that plantar flexor strength plays a major role in capability to recover balance even though the movement was not constrained to the ankle. / Ph. D.

During an under-body blast (UBB) event, an improvised explosive device (IED) delivers a high-energy blast beneath a military vehicle, exposing mounted Warfighters to considerable risk of severe lower extremity injuries. Loftis and Gillich (2014) determined that the lower leg and ankle region is the most common body region to sustain skeletal injury in military mounted combat events, comprising twenty-one percent of cases reported in the Joint Trauma Analysis and Prevention of Injuries in Combat (JTAPIC) database between 2010 and 2012. Injuries of the lower extremity are not always life-threatening. However, from a survivability standpoint, these injuries may affect the ability of the Warfighter to self-extricate and ambulate in the immediate aftermath of an UBB event. In addition, lower extremity injuries can lead to long term health complications and reduced quality of life (Dischinger et al., 2004). While some comparisons can be drawn from the study of civilian automotive crashes; the impact level, rate, location, and directions in UBB are fundamentally different for the lower extremity. Therefore, substantial research efforts to characterize and assess injuries unique to UBB are essential. The Warrior Injury Assessment Manikin (WIAMan), the Tech Demonstrator version of which was introduced by Pietsch et al. (2016), is the only anthropomorphic test device (ATD) designed to evaluate injury patterns in UBB conditions. However, there are no known injury assessment tools for the female Warfighter at this time. The overarching goal of this research effort is to determine the origin of potential differences in the response of females and males in UBB conditions. The results of this work contribute to the body of research concerning high-rate axial loading of the lower extremity and form the first detailed biomechanical account of UBB effects on female PMHS. This work will inform future decisions regarding the requirements for a valid injury assessment capability for female Warfighters in the UBB environment and the subsequent research needed to support those requirements. Ultimately, advancements can be made in modeling and simulation capabilities, injury assessment criteria, test methodologies, and design approaches for safer military ground vehicles and personal protective equipment (PPE). Improvements in these technologies will reduce morbidity and mortality rates among the U.S. Warfighter population, both male and female. / During an under-body blast (UBB) event, an improvised explosive device (IED) delivers a high-energy blast beneath a military vehicle. Energy from the explosive is imparted to the occupants primarily through the floor and seats of the vehicle, exposing the occupants to considerable risk of injuries to the lower extremity. Compared to civilian automotive crashes, the lower extremities of occupants in UBB scenarios are exposed to greater forces, applied at higher rates, and in different locations and directions. To improve current vehicle systems and personal protective equipment (PPE), it is crucial to develop tools to evaluate injuries in UBB scenarios. One such tool is a test dummy, which is designed to quantify loads, deflections, and accelerations experienced by occupants during a crash. These measured values are compared to accepted thresholds, above which injury is likely to occur. The Warrior Injury Assessment Manikin (WIAMan), which is representative of the 50th-percentile male, is the only test dummy designed to evaluate injuries in UBB conditions. However, there are no known injury assessment tools for the female Warfighter at this time. The overarching goal of this research effort is to determine the origin of potential differences in the response of females and males in UBB conditions. The results of this work contribute to the body of research concerning high-rate axial loading of the lower extremity and form the first detailed biomechanical account of UBB effects on female post-mortem human surrogates (PMHS). The results will inform the development of injury assessment tools for female Warfighters, which will ultimately lead to improvements in technologies to reduce morbidity and mortality rates among the U.S. Warfighter population, both male and female.

Relative motion between residual limb and prosthetic socket is an indication of poor fit. Both the fabrication and fitting processes are highly subjective and a favorable result depends upon the technician's expertise. Although numerous methods exist to measure the relative motion, all have limitations and are not well suited for clinical use. A measurement system using optical sensors has been proposed by students at the Technische Universität Darmstadt and evaluations of a functional model have yielded promising results. In this thesis, the existing functional model is improved and expanded to use an array of sensors. A new microcontroller is selected and incorporated into the system. The software and data communication are optimized for fast, reliable performance and the system is then evaluated on a test rig to determine favorable calibration settings and quantify performance. System frequencies up to 1299 Hz are achieved. It is found that the surface microstructure has a dominant effect over short measurement distances; calibrations performed over longer distances are to be preferred. For the chosen calibration factors, the greatest relative errors over a 40 mm distance are found to be 0.90% ± 0.51% in the X direction and -4.76% ± 1.61% in the Y-direction. A systematic drift is also identified. The final system accommodates up to eight sensors and is controlled from a feature-rich MATLAB GUI. / Master of Science / In lower limb prosthetics, the amount of relative motion between the prosthesis and residual limb is considered an indicator of the quality of fit. As existing methods for measuring this motion are generally difficult to use, a simpler system is desired. The task for this master's thesis is to develop an existing functional model into a measurement system with multiple sensors and validate its performance. The first step is to upgrade the microcontroller responsible for reading the sensor data and transmitting it to the PC. The original codes for both the microcontroller and PC-side Graphical User Interface (GUI) are then examined and optimized for maximum speed. The system is expanded to accommodate multiple sensors and its performance evaluated using a test-rig. Finally, the completed system is prepared for use in a future study by creating the appropriate component housings, wiring, and software functionalities.

No / Excavation of the Schöningen lignite mine in Germany produced the earliest examples of hunting spears to date, and a large assemblage of anthropogenically fragmented faunal remains deposited in anaerobic lacustrine silt sediments during the Middle Pleistocene. The exceptional preservation of the assemblage makes the site of prime importance to our understanding of the behavioural, social and economic patterns of hominins in the Lower Palaeolithic of the Middle Pleistocene in Europe. This chapter describes the digital refitting analysis, part of the AHRC-funded Fragmented Heritage project, undertaken to address the logistical challenge posed by manually comparing individual bone fragments within the assemblage to identify refitting sequences. This logistical refit challenge uses the Schöningen assemblage to investigate the effectiveness of a digital refit approach to the analysis of large faunal assemblages. We describe the process from digitisation of the bone fragments by macro structured light scanning, digital segmentation of refitting surfaces, and digital comparison of the refitting and non-refitting surfaces to produce statistical matches. We discuss how taphonomic data can be visualised from the analysis and can be used to inform interpretation of the taphonomic histories of these faunal remains and the human behaviours associated with the formation of this unique assemblage. / The research was funded through an AHRC doctoral award as part of the AHRC Digital Transformations funded Theme Large Grant Fragmented Heritage (AH/L00688X/1) and through in-kind contributions from MONREPOS.

Yes / Although gaze during adaptive gait involving obstacle crossing is typically directed two or more steps ahead, visual information of the swinging lower-limb and its relative position in the environment (termed visual exproprioception) is available in the lower visual field (lvf). This study determined exactly when lvf exproprioceptive information is utilised to control/update lead-limb swing trajectory during obstacle negotiation. 12 young participants negotiated an obstacle wearing smart-glass goggles which unpredictably occluded the lvf for certain periods during obstacle approach and crossing. Trials were also completed with lvf occluded for the entirety of the trial. When lvf was occluded throughout, footplacement distance and toe-clearance became significantly increased; which is consistent with previous work that likewise used continuous lvf occlusion. Both variables were similarly affected by lvf occlusion from instant of penultimate-step contact, but both were unaffected when lvf was occluded from instant of final-step contact. These findings suggest that lvf (exproprioceptive) input is typically used in an online manner to control/update final foot-placement, and that without such control, uncertainty regarding foot placement causes toe-clearance to be increased. Also that lvf input is not normally exploited in an online manner to update toe-clearance during crossing: which is contrary to what previous research has suggested.

No / We often complete step downs in the absence of visual feedback of the lower-limbs, and/or of the area on the ground where we intend to land (e.g. when descending a step whilst carrying a laundry basket). Therefore, the present study examined whether information from lower visual field (lvf) provides any advantage to the control of step descent. Ten healthy subjects (age 24.4 ± 9.4 years) completed repeated step downs over three-step heights with visual information available from either full or upper visual fields (lvf occluded), and for specific intervals relative to step initiation. Visuomotor control of step descent was assessed by determining pre-landing kinematic measures and landing mechanic variables for the initial landing period. Findings indicate that whilst there were only limited effects on pre-landing kinematic measures under lvf occlusion, individual’s ability to plan/control landing mechanics was significantly different in such conditions compared to when they had access to full field vision. These changes were consistent with participants being uncertain regarding precise floor height when access to lvf was restricted, and consequently led them to adapt their landing behaviour but without fundamentally altering their stepping strategy. Compared to when vision was available throughout, the occlusion of vision (full or upper visual field) from toe-off or mid-swing onwards caused very few differences in landing behaviour. This suggests that the contribution of information from lvf to the control of landing behaviour occurs predominantly prior to or during movement initiation and that ‘online’ vision is used only in the latter portion of the descent phase to subtly ‘fine tune’ landings.

Every year, over 3.5 million women give birth in the United States, with about 67.9% delivering vaginally. Over 80% of postpartum (PP) women experience chronic pain in the pelvis, lower back, hip, and legs at 24 weeks after birth, and 20% continue to experience these issues 3 years later. PP women often face pelvic instability and weakness, which disturb balance and lead to asymmetric loading in the pelvis and legs. This imbalance makes daily tasks, such as lifting and carrying a car seat during childcare, more difficult, and increases the risk of chronic pain and injury. This study aimed to explore how different groups – PP and nulliparous (NP) women – and different ways of holding a car seat while standing – no holding, symmetrical holding with two hands in front, and asymmetrical holding with one arm by the side – affect balance and limb loading symmetry. Results showed that postpartum women struggled more with balance as the task became more challenging, with asymmetrical holding showing large differences between groups. PP women also exhibited greater asymmetric limb loading compared to NP women with asymmetrical holding creating the greatest level of asymmetric limb loading. The study also aimed to explore how the two groups – PP and NP – and the different ways of lifting a car seat – symmetrically and asymmetrically – affect balance and limb loading. Both groups had more asymmetric limb loading and worse balance with asymmetrical lifting, though NP women showed larger movements during asymmetrical lifting, likely reflecting the movement of the body during the condition. These results highlight the importance to further research balance and limb loading in PP compared to NP women. Understanding whether pelvic instability and weakness may contribute to differences in balance and limb loading is crucial as it may help explain how and why postpartum women face higher risk of injury and chronic pain. Ultimately, such work may find ways to improve postpartum health during daily activities. / VT Engineering Faculty Organization-Opportunity (EFO-O) Seed Investment / Master of Science / Every year, over 3.5 million women give birth in the United States, with about 67.9% delivering vaginally. Over 80% of postpartum (PP) women experience chronic pain in the pelvis, lower back, hip, and legs at 24 weeks after birth, and 20% continue to experience these issues 3 years later. PP women often face pelvic instability and weakness, which disturb balance and lead to asymmetric loading in the pelvis and legs. This imbalance makes daily tasks, such as lifting and carrying a car seat during childcare, more difficult, and increase the risk of chronic pain and injury. This study aimed to explore how different groups – PP and nulliparous (NP) women – and different ways of holding a car seat while standing – no holding, symmetrical holding with two hands in front, and asymmetrical holding with one arm by the side – affect balance and limb loading symmetry. Results showed that postpartum women struggled more with balance as the task became more challenging, with asymmetrical holding showing large differences between groups. PP women also exhibited greater asymmetric limb loading compared to NP women with asymmetrical holding creating the greatest level asymmetric limb loading. The study also aimed to explore how the two groups – PP and NP – and the different ways of lifting a car seat – symmetrically and asymmetrically – affect balance and limb loading. Both groups had more asymmetric limb loading and worse balance with asymmetrical lifting, though NP women showed larger movements during asymmetrical lifting, likely reflecting the movement of the body during the condition. These results highlight the importance to further research balance and limb loading in PP compared to NP women. Understanding whether pelvic instability and weakness may contribute to differences in balance and limb loading is crucial as it may help explain how and why postpartum women face higher risk of injury and chronic pain. Ultimately, such work may find ways to improve postpartum health during daily activities.